Minecraft 14w25b, Minecraft 14w26c, Minecraft 14w28b, Minecraft 14w30b
In Multiplayer, spawning a Zombie with custom head, such as with the command:
will result in surrounding entities being rendered incorrectly, and will rotate and move about the Zombie (when it moves).
Any 'SkullOwner' (real player or fake) will have this result. Spawning a zombie without the tag on the skull will spawn a normal zombie (with a Steve head) with no issues.
The presence of other equipment on the zombie has no effect, and none of them seem to appear on the mob (including the skull).
Also, if you deal damage to the 'glitched' zombie, it will cause your screen to turn red, similar to the death screen. This will stick with the player until their client is restarted, or they deal damage to another mob (other than the glitched zombie).
To test this yourself:
-Spawn a zombie wearing custom player head in an area with other entities and signs around.
-Hit the zombie.
-Hit another mob to resolve the red screen.
If anybody else could confirm I am not crazy and this is an issue, that would be great.